Ken Whisenhunt, Head Coach, Arizona Cardinals

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Ken Whisenhunt is another one of those guys who has been under fire as of late. The offseason acquisition of Kevin Kolb at quarterback was supposed to help Whisenhunt retain his job, but at this point that doesn't look likely.

Kolb hasn't done a bad job, but the Cardinals defense has been bad enough that they've only been able to muster a 1-4 record.

Whisenhunt will likely need a big turnaround from his defense if he wants to be wearing Arizona red next season.

Jim Caldwell, Head Coach, Indianapolis Colts

Jim Caldwell took over the Indianapolis Colts organization when the legendary Tony Dungy retired, and since then the Colts have done pretty well overall.

However, now that franchise quarterback Peyton Manning is out for the season, it's become apparent that he has been the sole reason for their success.

While the Colts should be back to form next season when Manning comes back, it may be time for a coaching change in Indianapolis.

With Manning exiting his prime and the rest of the team in shambles, the Colts organization may begin rebuilding through the draft so that they're ready to compete without Manning by the time he retires.

Juan Castillo, Defensive Coordinator, Philadelphia Eagles

That's right, Juan Castillo was Philly's offensive line coach in 2010 before being promoted to defensive coordinator this year.

With rankings of 27th, 14th, 7th and 30th in scoring defense, total defense, passing defense and rushing defense, respectively, despite going out and getting some dominant defensive players, it's safe to say it hasn't been an ideal start for the 1-4 Eagles' defense.

Just five weeks into the Juan Castillo experiment, it may have failed.

Tony Sparano, Head Coach, Miami Dolphins

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Another coach who has been on the hot seat recently, Tony Sparano is all but out in Miami.

Sparano's Dolphins are 0-4 on the season, and with no proven quarterback and a defense that is ranked 24th or worse in three of the four major statistical categories, it's safe to say the Dolphins franchise will be making a change at some point this season or in the offseason.

In Sparano's case, it's most likely not "if," but "when" he will be relieved of his head coaching duties.